textproduct: Rapid City

KEY MESSAGES

- Isolated severe storms possible over south central SD late this evening into the overnight hours. Main hazards will be large hail and damaging winds.

- Slight risk (level 2 of 5) over western SD for Thursday with main threats being large hail and damaging winds.

- Unsettled weather continues through the rest of the week with near daily chances for afternoon showers/storms and temperatures in the 80s to 90s.

DISCUSSION

(This Evening Through Tuesday) Issued at 115 PM MDT Tue Jun 30 2026

Upper level analysis shows trof axis over the Rockies with southwest flow over the Northern Plains. Embedded shortwave sits centered over UT. The CWA sits under mostly clear skies with a few cumulus clouds developing over northwestern SD. Sunny and warm weather will prevail over the region through the afternoon before cloud cover increases in the evening as the upper level wave approaches the region. Storm chances will increase across the southern tier of our CWA through the evening hours. MU CAPE progged to increase to 1500-3000 J/kg over south central SD by midnight. CAMs show convection moving out of NE into the southern portions of our CWA. Widespread severe wx is not expected but we could see a few severe caliber gusts and large hail over south central SD overnight.

Storm chances return Wednesday afternoon as 500-1500 J/kg ML CAPE and effective shear of 30-45kt progged to develop over the Black Hills into south central SD. Isolated convection may develop over the Black Hills and along a dryline over southwestern into south central SD. A strong to severe storm may develop over the Black Hills and south central SD with large hail and damaging winds as the main hazards.

Weak shortwave moves through Thursday, 1500-3000 J/kg ML CAPE progged to develop over western SD by the afternoon hours with 30- 40KT effective shear. Convection should initiate along the higher terrain of the Bighorns and Black Hills and move eastward. NAM showing a strong signal of these cells growing into an MCS as they reach the western SD plains. The SPC has much of the western SD plains under a slight risk with the main hazards being large hail and damaging winds.

Deterministic guidance in good consensus of mostly zonal flow developing over the Northern Plains by the holiday weekend. Warm temperatures (in the 80s to 90s) with daily chances for afternoon storms will result.

AVIATION

(For the 00Z TAFS Through 00Z Wednesday Evening) Issued At 519 PM MDT Tue Jun 30 2026

Mainly VFR conditions are expected through most of the forecast period. Isolated thunderstorms will continue to develop this evening and persist into the overnight hours; best chances across SW SD into south-central SD. MVFR/IFR conditions will be possible in the stronger storms, along with erratic gusty winds up to 40kts. Starting around 01/17-19z, another round of isolated thunderstorms are possible over western South Dakota and the Black Hills, lasting through the remainder of the forecast period. MVFR/IFR conditions will be possible in the stronger storms.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.